<select>
	<option>请选择</option>
	<optgroup class="attr">
		<option>html</option>
		<option>css</option>
		<option>javascript</option>
	</optgroup>
	
	<optgroup class="attr">
		<option>jsp</option>
		<option>php</option>
		<option>asp.net</option>
		<option>nodejs</option>
	</optgroup>
</select>